05/02/2026
Networking protocols are basically rules or languages that computers use to talk to each other.
Think of ports as doors—each service has its own door to send or receive data.
1️⃣ FTP – File Transfer Protocol (Ports 20 & 21)
Purpose: Transfer files between computers.
Analogy: A mailman delivering packages.
Port 21: Control door – gives instructions like “deliver this package.”
Port 20: Data door – actually moves the files.
2️⃣ SSH – Secure Shell (Port 22)
Purpose: Remotely control another computer securely.
Analogy: A secure video call to your computer, where only you can talk.
Use case: Server management, troubleshooting remotely.
3️⃣ HTTP – Hypertext Transfer Protocol (Port 80)
Purpose: Load websites on your browser.
Analogy: Ordering food at a restaurant—your browser asks, server serves.
Note: Data is sent in plain text, not secure.
4️⃣ HTTPS – Secure HTTP (Port 443)
Purpose: Same as HTTP, but encrypted for safety.
Analogy: Sending your bank info in a locked envelope.
Use case: Online banking, e-commerce, login pages.
5️⃣ DNS – Domain Name System (Port 53)
Purpose: Converts website names into IP addresses.
Analogy: A phone book that tells you the number of the person you want to call.
Example: You type www. - .com → DNS gives the IP address.
6️⃣ TCP – Transmission Control Protocol
Purpose: Ensures data arrives safely and in order.
Analogy: A courier who checks every package is delivered completely.
7️⃣ UDP – User Datagram Protocol
Purpose: Sends data fast, without verifying delivery.
Analogy: Throwing flyers – fast, but some may get lost.
Use case: Video streaming, online gaming (speed is key, small loss acceptable).
8️⃣ SMTP – Simple Mail Transfer Protocol (Port 25)
Purpose: Sends emails.
Analogy: Sending letters through the post office.
9️⃣ IMAP – Internet Message Access Protocol (Port 143)
Purpose: Read emails directly on the server without downloading.
Analogy: Reading letters at the post office without taking them home.
🔟 DHCP – Dynamic Host Configuration Protocol (Ports 67 & 68)
Purpose: Automatically assigns IP addresses to devices.
Analogy: Getting an automatic parking spot in a parking lot.
Port 67: Server’s door
Port 68: Client’s door
1️⃣1️⃣ RDP – Remote Desktop Protocol (Port 3389)
Purpose: Remotely view & control another computer’s screen.
Analogy: Driving someone else’s car from your seat.
Use case: Remote tech support, work from home.
1️⃣2️⃣ ARP – Address Resolution Protocol
Purpose: Find a device’s hardware address (MAC) on the network.
Analogy: Finding the exact house number when you know the street name.
Quick Memory Port List:
Web: HTTP = 80, HTTPS = 443
Email: SMTP = 25, IMAP = 143
Remote Control: SSH = 22, RDP = 3389
File Transfer: FTP = 20/21
Auto IP: DHCP = 67/68
